Fever after eating greasy food may be caused by cholecystitis, pancreatitis, acute gastroenteritis and other causes. 1. cholecystitis: cholecystitis is a kind of inflammation that occurs when the gallbladder ducts are blocked and the bile is stagnant and concentrated to stimulate the gallbladder, and it can be affected by bad dietary habits, leading to nausea and vomiting and fever, which often occurs after a fatty meal or at night, leading to fever after eating greasy food. 2. Pancreatitis: Pancreatitis refers to inflammatory damage to the pancreas, overeating and greasy diet are risk factors for pancreatitis, leading to epigastric pain, nausea and vomiting, and fever. 3. Acute gastroenteritis: acute gastroenteritis means acute inflammatory damage to the mucous membrane of the gastrointestinal tract, eating greasy food will lead to trigger the disease or lead to aggravation of the condition, there will be a fever after eating greasy. Fever after eating greasy food may also be caused by other reasons, the symptoms need to consult a doctor in time to identify the cause of the corresponding treatment.